It is well recognized that electrical energy consumption tends to peak during the heat of the day. Because these peak energy demands exist during only a portion of the day this energy is generally supplied by smaller capacity power-plants. The obvious result is higher cost per kilowatt-hour than energy consumed during non-peak periods. This cost is of course passed on to the consumer. Considerable cost savings would result, both to the consumer and the electrical utility, in addition to conservation of natural resources, if consumers of electrical energy could be persuaded to redistribute their demands to a more uniform level throughout the day.
While economic reasons have been found effective in causing industrial consumers of electrical energy to disperse their demands away from peak demand periods, residential peak loads have thus far proven substantially unmanageable. Most pleas to "turn down the thermostat" and the like appear to be ineffectual. Therefore, utilities in general are seeking ways of controlling customer demands directly to redistribute demand throughout the day. This redistribution is generally referred to as "peak-shaving."
Most existing "peak shaving" systems involve some form of communications, such as ripple signals superimposed on the power system, radio, power line carrier, or combinations of these types of equipment. Unfortunately, each of the above systems tends to be economically unjustifiable because of costly installation of the controlled devices between the customer's appliances and the circuit breaker housing. In addition to the cost of installation, the utility is put in an unfavorable position if damage to the customer's appliances should occur.
Thus, there has been a need for an economical device that can be installed at low costs for redistributing energy demand away from peak demand periods with minimal risk to a customer's appliances.